This invention relates to injection molding, and more particularly to injection molding of plastic material around a level vial or other member containing an encapsulated volume of fluid.
A level vial consists of a tubular member formed of a translucent material having a volume of fluid in its interior. Typically, a vial is constructed by filling a cylindrical member with fluid and then securing a cap to the open end of the cylindrical member to seal the interior of the cylindrical member and retain the fluid therein. The fluid occupies less than the entire volume of the closed interior of the cylindrical member, to form a bubble. The cylindrical member is formed of a translucent plastic material, to enable the bubble to be viewed from the exterior of the vial after it has been constructed as described.
Level vials are mounted to the frame of a level in a variety of ways. In one arrangement, a metal frame includes a web located between a pair of spaced flanges. The web is provided with a series of openings and each opening includes a pair of notches for receiving the ends of the vial, such that the vial extends across the opening. A pair of plastic covers are located one on each side of the frame. The covers are connected together, such as by a snap fit arrangement, and the frame web and the vials are disposed between the covers to form a composite level construction in which the covers function to retain the vials in position within the web openings. Alternatively, a pair of separate covers can be provided for each vial. Each pair of covers are engaged together with the frame web and the vial therebetween, such that each pair of covers functions to retain one of the vials in position. In another arrangement, a level body is provided with a series of openings, and vial-retaining structure is associated with each opening so as to enable the ends of the vial to be snap-fit into the opening. In a wood level construction, openings are formed in the wood frame for receiving one or more vials. The vials are placed within the openings, and plastic retainers are received within the openings and engaged with the vials for maintaining the vials in position. Transparent covers are mounted on either side of the frame over the opening for protecting the vials and enabling the vials to be viewed from the exterior of the frame.
It is an object of the present invention to provide an arrangement for mounting a level vial to a level, which eliminates the need for separate covers to maintain a level vial in position relative to the frame. It is another object of the invention to provide a level vial mounting system which eliminates the need for engaging a level vial with a level body in a snap-fit manner. It is a further object of the invention to provide a simplified system for engaging a level vial with a vial mounting component which is adapted for engagement with a level frame. A still further object of the invention is to provide a simple and efficient arrangement for engaging any liquid-containing member with a body or other structure formed of a moldable material. Yet another object of the invention is to provide an arrangement for insert molding a liquid-containing member along with a body.
In accordance with the invention, moldable material is molded about a liquid-containing member to form a body, such that the body is integrally formed about the liquid containing member. The liquid-containing member may be molded into the body in an insert molding process, in which the liquid-containing member is engaged between a pair of mold sections which cooperate to define a mold cavity having a shape corresponding to the desired final shape of the body. In one form, the mold sections include structure adapted to form an opening in the molded member, and the liquid-containing member is positioned relative to the mold sections so as to extend across the structure which forms an opening in the molded member. The liquid-containing member defines a pair of end portions, each of which is located within a portion of the mold cavity located adjacent the structure in the mold sections which forms an opening in the molded member, such that the moldable material surrounds and encapsulates the end portions of the liquid-containing member when injected into the mold cavity.
The invention can be used to construct a level or a vial mounting component for use in combination with a level frame. In one embodiment, the mold cavity is configured to form a level having at least one gauging surface and a web. The mold sections are configured to form one or more openings in the web, and a level vial is engaged with the mold sections so as to extend across each opening formed in the molded member. When moldable material is injected into the mold cavity, the moldable material surrounds and encapsulates the ends of the vial on either side of each opening, to form an integral, molded level with insert molded level vials. The insert molding of the level vials provides accurate placement of the vials relative to the gauging surface of the level, and also securely mounts the vials to the level so as to prevent the vials from being disengaged from the level.
In another embodiment, the mold sections are configured to receive a level frame which has one or more openings, with each opening having a pair of notches for receiving the ends of a level vial. The frame and the vials are loaded into the mold sections, and the mold cavity is formed so as to provide moldable material about the ends of each vial and at least a portion of the frame, so as to securely retain the level vials in position on the frame. The cavity may be formed so as to extend beyond the ends of the frame, to form molded end caps which are integrally molded along with the moldable material which overlies the ends of the level vials.
In another embodiment, a level vial is insert molded in a vial mounting component for use in mounting a vial to the frame of a level, such as within an opening formed in a wood level frame. The vial mounting component includes a pair of spaced walls, and the level vial extends between the walls. Each wall is formed of moldable material which forms a protrusion surrounding and encapsulating an end portion of the vial. The vial mounting component may be adapted for use in combination with another similarly constructed vial mounting component, to mount a pair of vials within the frame opening.
The present invention simplifies assembly of a level by insert molding the level vials along with the plastic material of a level body or a cover member, or along with a retainer member engageable within an opening formed in a level frame.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.